Editing Multiverse (section)

== M-theory ==
{{see also|Introduction to M-theory|M-theory|Brane cosmology|String theory landscape}}
A multiverse of a somewhat different kind has been envisaged within [[string theory]] and its higher-dimensional extension, [[Introduction to M-theory|M-theory.]]<ref>{{cite arXiv|eprint=hep-th/0511037v1|last1=Weinberg|first1=Steven|title=Living in the Multiverse|date=2005}}</ref>

These theories require the presence of 10 or 11 spacetime dimensions respectively. The extra six or seven dimensions may either be compactified on a very small scale, or our universe may simply be localized on a dynamical (3+1)-dimensional object, a [[D3-brane]]. This opens up the possibility that there are other [[brane]]s which could support other universes.<ref name="Richard J Szabo 2004">Richard J. Szabo, ''An introduction to string theory and D-brane dynamics'' (2004).</ref><ref name="Maurizio Gasperini 2007">Maurizio Gasperini, ''Elements of String Cosmology'' (2007).</ref>